1. Field of the Invention
The present invention relates to a motor vehicle friction clutch having an automatic adjustment for wear and also having a clearance sensor. Such a friction clutch can generally include a pressure plate, or thrust plate, which pressure plate is fastened with the interposition of a clutch disc with friction linings, to a flywheel. The pressure plate and the flywheel together define an axis of rotation. The pressure plate is located non-rotationally but axially movably in a clutch housing, and a membrane spring is inserted under prestress between the pressure plate and the clutch housing. The membrane spring makes contact with the pressure plate, whereby this contact takes place with the interposition of an adjustment device. The adjustment device makes possible an axial displacement of the pressure plate away from the membrane spring as a function of the wear of the friction linings of the clutch disc.
2. Background Information
A friction clutch with an automatic adjustment for wear is disclosed, for example, in German Unexamined Patent Application 3518781. In such a friction clutch, there is a friction-loaded, displacement limiting device for the thrust plate with respect to the clutch housing. The displacement limiting device is used to make it possible, when the specified clearance in the displacement limiting device is exceeded during the disengagement process of the friction clutch, for the membrane spring to lift up from from its contact on the thrust plate, so that as a result of the radial displacement of wedge-shaped components, this contact adjusts for the clearance between the membrane spring and the thrust plate by the amount of the wear of the friction linings. A disadvantage of this design can be that the automatic wear compensation is essentially only possible after the displacement limiter device has travelled the distance of the clearance, and then essentially only when the clutch is completely disengaged. Such a design cannot typically be used, for example, with a hydraulic disengagement system, since such a system would automatically adjust for even quite small amounts of wear within the clearance, without actuating the clearance adjustment mechanism as a function of the wear of the friction linings.